Blindstitch foot attachment for sewing machines

ABSTRACT

An improved blindstitch foot attachment for use with a zigzag sewing machine of the type having a built-in blindstitch, the foot attachment comprising a connecting element or shank which attaches to the presser bar of a zigzag sewing machine and supports a blindstitch foot by adjustable means which permits lateral adjustment of the position of the foot relative to the presser bar, the foot comprising a body portion having a pair of forwardly extending upwardly curved arms separated by a longitudinal slit and having a needle opening located at the rear of the slit in communication therewith, and a guide member having a curved guide wall for directing material into a proper position for blindstitching, the guide member being attached to the foot body portion so that the inner end of the guide wall is disposed and supported in the longitudinal slit.

United States Patent [1 1 v Smith [111 3,795,209 i451 Mar. 5, 1974 1 BLINDSTITCH FOOT ATTACHMENT FOR SEWING MACHINES [76] lnventor: Orville Keith Smith, 41 18 Woodland Ave., Western Springs, 1117 60558 [22] Filed: Aug. 10, 1972 [21] Appl. No.: 279,505

Azara..... 112/151 Price 112/151 Primary ExaminerH-. Hampton Hunter Attorney, Agent, or Firm-Gary, Juettner, Pigott & Cullinan 57 ABSTRACT An improved blindstitch foot attachment for use with a zigzag sewing machine of the type having a built-in blindstitch, the foot attachment comprising a connecting element or shank which attaches to the presscr bar of a zigzag sewing machine and supports a blindstitch foot by adjustable means which permits lateral adjustment of the position of the foot relative tothe presser bar, the foot comprising a body portion having a pair of forwardly extending upwardly curved arms separated by a longitudinal slit and having a needle opening located at the rear of the slit in communication therewith, and a guide member having a curved guide wall for directing material into a proper position for blindstitching, the guide member being attached to the foot body portion so that the inner end of the guide wall is disposed and supported in the longitudinal slit.

2 Claims, 5 Drawing Figures 1 1 BLINDSTITCH FOOT ATTACHMENT FOR SEWING MACHINES BRIEF SUMMARY OF THE INVENTION:

Blindstitching is a known technique for producing a substantially invisible hem on various types of material as when hemming dresses, coats, drapes, etc. In order to produce such stitches, the material is folded on itself in a particular manner and is sewed on the inside of the hem, the folded material normally being held in proper folded relation by pins until the sewing is completed.-

The folded material when positioned for blindstitehing on a zigzag sewing machine presents an upper fold on the inside of the hem which is located inwardly from the outer edge of the material and which is capable of .bar or slide bar 12 which in turn is connected to a zigcal blindstitch zigzag path to draw stitching thread through the material to be stitched by sewing on the inside of the hem of material to be'stitched in order to A guide the same into a correct position for stitching.

Another of my objects is to provide a blindstitch foot as last above-mentioned which is supported from a presser bar of a sewing machine by an adjustable support which permits accurate lateral adjustment of the foot member relative to the presser bar.

A further object of the invention is to provide a blindstitch foot comprising a body portion and a relatively large curved guide member which is fixedly attached to the body portion.

The foregoing and other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereofitaken in foot assembly of the present invention mounted on the presser .bar of a zigzag sewing machine, the-footbeing positioned so as to rest upon and slide over material which is folded in a manner suitable for a blindstitching operation and positioned on a'i'nachine table or platform so as to permit sewing on the inside of the hem;

FIG. 2 is a perspective view of the blindstitch foot assembly of FIG. 1;

FIG. 3 is a sectional view taken substantially along the line 3-3 of FIG. 2; FIG. 4 is a' sectional vview taken substantially along the line 44 of FIG. '3; and

FIG. 5 is a top plan view showing-a length of material after a blindstitching operation has been carried out thereon, the material, being shownv both in folded position as during sewing on the inside of the hem, and also as when unfolded so as to view the outside of the mate- I ings, a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION:

Referring now to the drawings, there is shown in FIG.-

1 a blindstitch foot assembly 10 mounted to a presser side of the hem of thefolded material 26.

The mounting bracket 14 tits on the lower end of the presser bar 12, and there is shown in FIG. 1 a thumb screw or the like 28 for firmly attaching the bracket to the presser bar. The mounting bracket 14 includes upper and lower bent flange members 30 and 32 (see FIG. 3) which serve as guides for the slidable mounting plate 16. A thumb screw member 34 has a short threaded stud 36 which extends through a longitudinal slot 38 in the slidable mounting plate 16 and is threaded into the bracket 14. The plate 16 may thus be moved laterally to a desired position and then clamped tightly in place by the thumb screw 34. Specifically, the thumb screw 34 includes a body portion 40 having an end face 42 (see FIG. 4) which bears against and fricment of the plate 16 when the thumb screw 34 is'loos-- ened thereby preventing excessive; looseness of the parts. The blindstitch presser foot18 comprises a body portion 46 having a pair of upstanding lugs 48 and 50 adjacent the rear end of the body portion. The lugs 48 and 50 are spaced apart to receive therebetween the lower end of the mounting arm 20 of the slidable plate'16. The arm 20 is connected to the body portion 46 by a pin 52 which permits limited pivotal movement by the presser foot 18 relative to the arm 20. The body portion 46 has formed therein a needle opening 54 so thatthe needle 24 may move in a zigzag path into the opening 54 to draw thread through the material to be stitched. The needle opening 54 accommodates the zigzag movement of the needle, the material being folded as shown in FIG. 1 and held against a machine table or platform (not shown) while the material'is moved rearwardly beneath the presser foot 18 in the direction of the-arrow during a blindstitchingoperation to hem the material with substantially invisible stitches.

The body portion 46 is formed with a substantially flat undersurface 56, and. it terminates at its rearward end in an upwardly inclined rear edge portion 58. The undersurface 56 is formed with an undercut area 60 (see FIG. 3) immediately rearwardly of the needle opening 54 and of approximately the same width as the latter. A longitudinal slit 62 is formed in the body portion 46 forwardly of the needle opening 54. The longitudinal slit 62 extends from the needle opening 54 to a forward edge 64 of the body portion, the slit being in communication with the needle opening and being offset from the center of the latter.

The longitudinal slit 62 divides the forward end of the body portion 46 into a pair of arms 66 and 68, and as I shown in FIG. 3 such arms curve upwardly to provide an entrance area which facilitates entry of the material 26 beneath the presser foot 18 to initiate a stitching operation. The two arms 66 and 68 are of equal length and extend upwardly along the same curved path so as to provide a relatively simple configuration which lends itself to inexpensive manufacturing processes.

In combination with the body portion 46 of the presser foot 18, there is provided a guide member comprising a mounting arm 72 and a relatively large curved guide arm 74. The guide member is made from sheet metal which is bent to form the mounting arm 72 and the guide arm 74 which are thus integral with one'another. A rearward portion 75 of the guide arm 74 is substantially flat and is positioned in the longitudinal slit 62 so as to be supported laterally by the curved arms 66 and 68. Moreover, the horizontal mounting arm 72 overlies the rearward portion of the arm 66 immediately forwardly of the needle opening 54. The arm 72 is fixedly secured to the arm 66 by a small rivet 76 whereby the guide arm 74 is permanently assembled to the presser foot body portion 46.

The guide arm 74 includes a substantially flat bottom edge 78 which is approximately coplanar with the undersurface 56 of the presser foot body portion 46 as best shown in FIG. 3. In addition, an upper edge portion 80 of the guide arm 74 extends forwardly and upwardly at approximately the same inclination as the curved arms 66 and 68 of the presser foot body portion 46. It will readily be seen that the guide-arm 74 projects forwardly well beyond the forward edge 64 of the presser foot body portion 46 so that the overall length of the guide arm extends from its rear edge 82-to'its for-' ward edge 84 (see FIG. 4) and thus the projecting portion of the guide arm somewhat exceeds the length of the portion which is disposed between and supported by the curved arms 66 and 68. It will further be noted from FIG. 4 that the projecting portion of the guide arm 74 is curved so that its outer edge 84 is approximately coplanar with a side edge 86 of the presser foot body portion 46.

In order to perform a blindstitching operation with the blindstitch foot of the present invention, the material is folded as shown in FIGS. 1 and 5. The needle 24 is temporarily unthreaded, and the machine is set to its blindstitch position by conventional means such as inserting a cam or setting a lever (not shown). The machine is preferably adjusted for the longest stitch, and the material is placed under the presser foot 18 as shown in FIG. 1 with the top fold 88 positioned against the inside of the guide arm 74, it being understood that the material facing up in FIG. I is actually the inside of the material so that the sewing will, be carried out on the inside of the hem.

On a two or three-position machine, the needle is set to the righthand position, and the zigzag width is preferably set to slightly less than one-half of the full zigzag width. The presser bar 12 is then lowered, and the thumb screw 34 is loosened, after which the hand wheel (not shown) is turned so that the lowered needle 24 is in the straight stitch position as shown at B in FIG. 5. The slidable mounting plate 16 is adjusted laterally until the needle in the B position just barely clears the right edge of the needle opening 54. The hand wheel is then turned again until the needle 24 has swung to the left for the blindstitch, and the zigzag width dial or lever (not shown) is adjusted until the needle is very slightly to the left of the guide arm 74, i.e., in the position shown at A in FIG. 5. The body portion 46 of the presser foot is provided with a marker 90 immediately behind the needle opening to indicate the desired location of the needle when in the A position or blindstitch position. The needle is then threaded, the thumb screw 34 is tightened, and the material is sewed with the top fold 88 positioned against the guide arm 74. If the operation is properly carried out, the needle should barely catch the top material, as shown for example at 92 in FIG. 5. When the hemmed material is unfolded and viewed from the outside, as in the upper portion of FIG. 5, only minute portions of the stitching thread are visible as indicated at 92'.

The lateral adjustability of the presser foot 18 renders the same highly advantageous for use in a blindstitching operation. The curved guide arm 74 has been found to be uniquely adapted for directing the folded material into precisely the correct position for invisible or blindstitching, and it will of course be understood that good results in a blindstitching operation require highly accurate positioning of the material, and espe' cially the upper fold of material 88, inasmuch the needle must barely catch the topmaterial. A presser foot in accordance with the present invention enables even inexperienced operators to accomplish highly satisfactory blindstitching with speed and accuracy on all types of materials.

I claim:

l. A blindstitch presser foot assembly for attachment to a zigzag sewing machine of the type equipped with a built-in blindstitch, said presser foot assembly comprising, in combination, a mounting bracket for attachment to a presser bar of zigzag sewing machine, slidable mounting means supported from said mounting bracket, said slidable mounting means including a laterally slidable plate member guided by said mounting bracket and having a laterally extending slot therein, said mounting bracket having upper and lower horizontal flange means which serve as guides for said laterally slidable plate which is disposed against a vertical face of said mounting bracket between said flange means, thumbscrew means extending through said slot and threaded into said mounting bracket for fixing said slidable plate in a selected lateral position, said thumbscrew means including a clamping surface which frictionally clamps said slidable plate in a selected position relative to said mounting bracket, a forwardly extending support arm at the lower end ofsaid slidable plate member, a presser foot supported from said support arm for limited pivotal movement about a horizontal transverse axis, said presser foot including a body porthe forward end of said body portion into a pair of arms, said pair of arms beingcurved upwardly to provide an entrance area for entry of material beneath the presser foot during a stitching operation, a thin sheet metal guide arm having an upright guide surface, the rearward end of said guide arm being disposed in said narrow longitudinal slot so as to be laterally supported on its opposite sides by said pair of arms, a horizontal tab integral with said sheet metal guide arm and overlying one of said pair of arms of said body portion adjacent the forward edge of said needle opening, and means affixing said horizontal tab to said body portion thereby affixing said guide arm to said presser foot for conjoint movement therewith, the forward end of said guide arm projecting forwardly substantially beyond edge approximately coplanar with a substantially flat undersurface portion of said presser foot body, and

where an upper edge of said guide arm extends forwardly and upwardly at approximately the same inclination as said pair of curved arms, the projecting forward end of said guide arm being curved laterally out- I wardly away from the position of the material to be stitched. 

1. A blindstitch presser foot assembly for attachment to a zigzag sewing machine of the type equipped with a built-in blindstitch, said presser foot assembly comprising, in combination, a mounting bracket for attachment to a presser bar of zigzag sewing machine, slidable mounting means supported from said mounting bracket, said slidable mounting means including a laterally slidable plate member guided by said mounting bracket and having a laterally extending slot therein, said mounting bracket having upper and lower horizontal flange means which serve as guides for said laterally slidable plate which is disposed against a vertical face of said mounting bracket between said flange means, thumbscrew means extending through said slot and threaded into said mounting bracket for fixing said slidable plate in a selected lateral position, said thumbscrew means including a clamping surface which frictionally clamps said slidable plate in a selected position relative to said mounting bracket, a forwardly extending support arm at the lower end of said slidable plate member, a presser foot supported from said support arm for limited pivotal movement about a horizontal transverse axis, said presser foot including a body portion having a needle opening and also having a narrow longitudinal slot extending from said needle opening to a forward edge of said body portion thereby dividing the forward end of said body portion into a pair of arms, said pair of arms being curved upwardly to provide an entrance area for entry of material beneath the presser foot during a stitching operation, a thin sheet metal guide arm having an upright guide surface, the rearward end of said guide arm being disposed in said narrow longitudinal slot so as to be laterally supported on its opposite sides by said pair of arms, a horizontal tab integral with said sheet metal guide arm and overlying one of said pair of arms of said body portion adjacent the forward edge of said needle opening, and means affixing said horizontal tab to said body portion thereby affixing said guide arm to said presser foot for conjoint movement therewith, the forward end of said guide arm projecting forwardly substantially beyond the forward edge of said body portion and being positioned for guiding engagement with an upper fold of a folded piece of material to be stitched when said material is fed beneath said presser foot for sewing on the inside of a hem during a blindstitching operation.
 2. A presser foot assembly as defined in claim 1 wherein said guide arm has a substantially flat bottom edge approximately coplanar with a substantially flat undersurface portion of said presser foot body, and where an upper edge of said guide arm extends forwardly and upwardly at approximately the same inclination as said pair of curved arms, the projecting forward end of said guide arm being curved laterally outwardly away from the position of the material to be stitChed. 